Analysis of proton magnetic resonance spectra of trans-2,5-dimethylpiperazine and its hydrochlorides. Effect of amine substituents on chemical shifts and coupling constants

1968 ◽  
Vol 72 (7) ◽  
pp. 2344-2351 ◽  
Author(s):  
J. L. Sudmeier
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Magnetic Resonance Spectra

Protonenresonanz-Spektroskopie ungesättigter Ringsysteme I

1965 ◽  
Vol 20 (10) ◽  
pp. 948-956 ◽  
Author(s):  
Harald Günther
Keyword(s):  
Magnetic Resonance ◽  
Concentration Dependence ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Electron System ◽  
Coupling Constants ◽  
Resonance Signal ◽  
Aromatic Character ◽  
Additional Support ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of 1.6-methano- and 1.6-oxido-cyclodecapentaene are described and analyzed in terms of chemical shifts and coupling constants. The results are discussed in connection with the structure and possible aromatic character of these compounds. Measurements of the concentration dependence of the chloroform resonance signal in solutions of both compounds give additional support for the presence of a delocalized 10 π-electron system.

The analysis of the proton magnetic resonance spectra of heteroaromatic systems. V. Diazanaphthalenes

1965 ◽  
Vol 18 (5) ◽  
pp. 707 ◽  
Author(s):  
PJ Black ◽  
ML Heffernan
Keyword(s):  
Carbon Tetrachloride ◽  
Magnetic Resonance ◽  
Long Range ◽  
Iterative Procedure ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Direct Calculation ◽  
Coupling Constants ◽  
Dilute Solutions ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of the four isomeric diazanaphthalenes, quinoxaline, phthalazine, quinazoline, and cinnoline, all as dilute solutions in carbon tetrachloride and acetone, have been investigated at 100 Mc/s. The chemical shifts and coupling constants have been obtained by direct calculation or, where appropriate, by an iterative procedure. Long-range coupling constants between protons separated by five and six bonds have been observed.

Proton magnetic resonance spectra of indolizine and its methyl derivatives and aza analogues

1964 ◽  
Vol 17 (10) ◽  
pp. 1128 ◽  
Author(s):  
PJ Black ◽  
ML Heffernan ◽  
LM Jackman ◽  
QN Porter ◽  
GR Underwood
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Iterative Procedure ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Methyl Derivatives ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of indolizine, indolizine-1,3-d2, 1- and 2-methylindolizine, 2,3-, 2,5-, 2,6-, and 2,7-dimethylindolizine and 1-, 2-, and 3-azaindolizine have been determined at 100 and/or 60 Mc/s. Unequivocal assignments have been made to all protons and the coupling constants and chemical shifts for indolizine and its aza analogues have been obtained by an iterative procedure. Long-range coupling constants involving protons separated by five and six bonds have been observed.

CYCLOHEXANE COMPOUNDS: VI. NUCLEAR MAGNETIC RESONANCE SPECTRA OF SOME DERIVATIVES OF THE STEREOISOMERIC 3-BROMO-1,2-CYCLOHEXANEDIOLS AND THE 2-BROMO-1,3-CYCLOHEXANEDIOLS

1966 ◽  
Vol 44 (7) ◽  
pp. 775-780 ◽  
Author(s):  
R. A. B. Bannard
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Angular Distortion ◽  
Order Analysis ◽  
First Order ◽  
Nuclear Magnetic Resonance Spectra ◽  
Derivatives Of ◽  
Magnetic Resonance Spectra

First-order analysis of the 60 Mc.p.s. proton magnetic resonance spectra of 1α-methoxy-2β-acetoxy-3α-bromocyclohexane, 1α-methoxy-2α-acetoxy-3β-bromocyclohexane, 1α-methoxy-2β-bromo-3α-acetoxycyclohexane, 1α-methoxy-2α-bromo-3β-acetoxycyclohexane, and the corresponding diol diacetates confirmed the stereochemical interrelationships of substituents which were assigned previously on chemical grounds, and demonstrated that the compounds exist in chair conformations. The chemical shifts of the methoxy methyl and acetoxy methyl protons did not provide reliable criteria for the assignment of conformations to these substituents in this series. The coupling constants of the methine protons followed, in general, the pattern predicted by the Karplus equation, and the smaller J2,3 values observed in the cis,trans compounds relative to those in the trans,trans compounds are interpreted mainly on the basis of conformational equilibration, upon which is superimposed a small dihedral angular distortion or a remote substituent orientational effect.

THE PROTON RESONANCE SPECTRA OF SOME SUBSTITUTED FURANS AND PYRROLES

1961 ◽  
Vol 39 (4) ◽  
pp. 905-914 ◽  
Author(s):  
R. J. Abraham ◽  
H. J. Bernstein
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Proton Resonance ◽  
Spin Coupling Constants ◽  
Substituted Furans ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of some substituted furans and pyrroles have been analyzed for spin coupling constants and chemical shifts.The relative insensitivity of the spin coupling constants to the nature of the substituent makes it possible to estimate their values in the parent molecules furan and pyrrole. The magnitude of the spin coupling constants is correlated with the angles made by the CH bonds with the CC bonds of the ring.The chemical shifts are interpreted in terms of an effect due to the electronegativity of the substituent together with the effect due to conjugation with the ring.

Proton magnetic resonance studies at 220 MHz of alanine transfer RNA

1969 ◽  
Vol 47 (4) ◽  
pp. 480-484 ◽  
Author(s):  
Ian C. P. Smith ◽  
Tetsuo Yamane ◽  
R. G. Shulman
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Transfer Rna ◽  
Magnetic Resonance Studies ◽  
The Common ◽  
Line Widths ◽  
Increasing Temperature ◽  
Magnetic Resonance Spectra

Proton magnetic resonance spectra at 220 MHz of alanine transfer RNA do not permit assignments of individual peaks due to each of the common bases; only a peak attributable to protons at position eight in adenine can be assigned with certainty. Measurements of the relative areas of proton magnetic resonance peaks due to the base and ribose-1′ protons indicate that the ribose moieties of tRNA are not involved in bonds stronger than those experienced by the bases. Proton magnetic resonance peaks attributable to the methyl and dihydro protons of the rare bases can be distinguished in the 220 MHz spectra; the variation of their line widths and chemical shifts with increasing temperature indicates that the rare bases are located in regions of the alanine transfer RNA molecule which are more highly organized than indicated by an open cloverleaf model.

Proton magnetic resonance spectra of some benzo[b]thiophens. An investigation of substituent effects in a heteroaromatic system

1968 ◽  
Vol 21 (7) ◽  
pp. 1853 ◽  
Author(s):  
B Caddy ◽  
M Martin-Smith ◽  
RK Norris ◽  
ST Reid ◽  
S Sternhell
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Spin Coupling ◽  
Heteroaromatic System ◽  
Spin Spin Coupling ◽  
Magnetic Resonance Spectra

N.m.r. data for 19 5-substituted and 13 polysubstituted benzo[b]thiophens are tabulated. The influence of the substituents at C5 on the chemical shifts of H4 and H6 is discussed. Long-range interproton spin-spin coupling between H3 and H7, and between H2 and H6, is general in benzo[b]thiophens. The vicinal coupling J6,7 in 5-substituted benzo[b]thiophens varies directly and linearly with the electronegativity of the substituents at C5.

scholarly journals Carbon-13 nuclear magnetic resonance spectra of oxazoles

1979 ◽  
Vol 57 (23) ◽  
pp. 3168-3170 ◽  
Author(s):  
Henk Hiemstra ◽  
Hendrik A. Houwing ◽  
Okko Possel ◽  
Albert M. van Leusen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Proton Coupling ◽  
Nuclear Magnetic Resonance Spectra ◽  
C Nmr ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The 13C nmr spectra of oxazole and eight mono- and disubstituted derivatives have been analyzed with regard to the chemical shifts and the various carbon–proton coupling constants of the ring carbons. The data of the parent oxazole are compared with thiazole and 1-methylimidazole.

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